Piping unit for transporting fuel

Abstract

Piping unit for transporting a fuel is constructed by connecting a resin tube and a connector for connecting the resin tube to a mating pipe. The connector has a connector body including a retainer holding portion and a retainer for engaging with the mating pipe. The resin tube has a multilayered construction including an inner fuel barrier layer and an outer layer covered with a protective layer. The outer layer has a small outer diameter (od) up to 6 mm, the fuel barrier layer and the outer layer have a wall-thickness (t), and a ratio of the outer diameter (od)/the wall thickness (t) is in a range of 4 to 8.

What is claimed is: 
     
       1. A fuel piping assembly, comprising:
 a piping unit for transporting a fuel; and 
 fixing clamps for supporting the piping unit; 
 wherein the piping unit has a resin tube, and 
 a connector attached to an end portion of the resin tube for connecting the resin tube to a mating pipe, the connector having a connector body including a retainer holding portion on one end of the connector body along an axial direction of the connector body and a tube connecting portion on the other end of the connector body along the axial direction for connecting to the resin tube, a retainer held in or on the retainer holding portion for engaging with the mating pipe to securely fix the connector body in the axial direction, and a sealing member for providing a seal between the connector body and the mating pipe, 
 wherein the resin tube has a multilayered construction including an inner fuel barrier layer and an outer layer made of polyamide covered further with a protective layer on an outer peripheral surface of the outer layer, the resin tube inside the protective layer having a small outer diameter (od) up to 6 mm and a wall-thickness (t), a ratio of the outer diameter (od) of the resin tube/the wall thickness (t) of the resin tube being in a range of 4 to 8, 
 wherein the resin tube which is flexible throughout is bent in arcuate shape at a plurality of bent points along a longitudinal direction of the resin tube and along a motor vehicle body, and both side portions of each of the plurality of the bent points being supported by a pair of the fixing clamps which are unconnected and separated from one another, the fixing clamps being positioned and attached to the motor vehicle body to define the ends of the bent points without any additional support for the bent points between the fixing clamps, each of the fixing clamps of the both side portions of each of the bent points being fastened to a different point of the motor vehicle body, 
 whereby the lengths and curvatures of the bent points and the positions of the ends of the bent points can be adjusted between the fixing clamps, 
 wherein each fixing clamp has a tube holding portion and a mounting portion for securely fixing the tube holding portion to the motor vehicle body, the mounting portion having an insert portion which is inserted in a holding bore in the motor vehicle body, an outside pinching portion which is formed integrally on an outer end portion of the insert portion to be located adjacent to an outer surface of the motor vehicle body, and an inside pinching portion which is formed integrally on an inner end portion of the insert portion to be located adjacent to an inner surface of the motor vehicle body, and 
 wherein the inside pinching portion includes foot portions on both lateral sides of the inner end portion of the insert portion and turned-back portions, each of the foot portions extending in a laterally outward direction at an angle toward the inner surface of the motor vehicle body, and each of the turned-back portions extending in a laterally inward direction from a laterally outer end of the foot portion at an angle toward an outer side of the motor vehicle body; 
 wherein all of the fixing clamps open in the same orientation with respect to the resin tube along the motor vehicle body. 
 
     
     
       2. The fuel piping assembly as set forth in  claim 1 , wherein each of the turned-back portions of the inside pinching portion engages with an inner edge of the holding bore. 
     
     
       3. The fuel piping assembly as set forth in  claim 1 , wherein the outside pinching portion includes extended portions on both lateral sides of the outer end of the insert portion, and each of the extended portions extending in a laterally outward direction at an angle toward an outer surface of the motor vehicle body. 
     
     
       4. The fuel piping assembly as set forth in  claim 1 , wherein a neck portion (A) is provided between the tube holding portion and the outside pinching portions. 
     
     
       5. A fuel piping assembly, comprising:
 a piping unit for transporting a fuel; and 
 fixing clamps fixing the piping unit to a motor vehicle body; 
 wherein the piping unit has a resin tube, and a connector attached to an end portion of the resin tube for connecting the resin tube to a mating pipe, the connector having a connector body including a retainer holding portion on one end of the connector body along an axial direction of the connector body and a tube connecting portion on the other end of the connector body along the axial direction for connecting to the resin tube, a retainer held in or on the retainer holding portion for engaging with the mating pipe to securely fix the connector body in the axial direction, and a sealing member for providing a seal between the connector body and the mating pipe, 
 wherein the resin tube has a multilayered construction including an inner fuel barrier layer and an outer layer made of polyamide covered further with a protective layer on an outer peripheral surface of the outer layer, the resin tube inside the protective layer having a small outer diameter (od) up to 6 mm and a wall-thickness (t), a ratio of the outer diameter (od) of the resin tube/the wall thickness (t) of the resin tube being in a range of 4 to 8, 
 wherein the resin tube which is flexible throughout, is bent in arcuate shape to provide a plurality of bent points along a longitudinal direction of the resin tube and along the motor vehicle body, both side portions of each of the plurality of the bent points being supported by a pair of the fixing clamps which are unconnected and separated from one another, the fixing clamps being positioned and attached to the motor vehicle body to define the ends of the bent points without any additional support for the bent points between the fixing clamps, each of the fixing clamps of the both side portions of each of the bent points being fastened to different points of the motor vehicle body portion by a pair of the fixing clamps; 
 whereby the lengths and curvatures of the bent points and the positions of the ends of the bent points can be adjusted between the fixing clamps, 
 wherein each fixing clamp has a tube holding portion and a mounting portion for securely fixing the tube holding portion to the motor vehicle body, the mounting portion having an insert portion which is inserted in a holding bore in the motor vehicle body, an outside pinching portion which is formed integrally on an outer end portion of the insert portion to be located adjacent to an outer surface of the motor vehicle body, and an inside pinching portion which is formed integrally on an inner end portion of the insert portion to be located adjacent to an inner surface of the motor vehicle body, and 
 wherein the inside pinching portion includes foot portions on both lateral sides of the inner end portion of the insert portion and turned-back portions, each of the foot portions extending in a laterally outward direction at an angle toward the inner surface of the motor vehicle body, and each of the turned-back portions extending in a laterally inward direction from a laterally outer end of the foot portion at an angle toward an outer side of the motor vehicle body; 
 wherein all of the fixing clamps open in the same orientation with respect to the resin tube along the motor vehicle body. 
 
     
     
       6. The fuel piping assembly as set forth in  claim 5 , wherein the fixing clamps are C-shaped clamps with openings, and each of the openings being oriented along the motor vehicle body portion. 
     
     
       7. The fuel piping assembly as set forth in  claim 5 , wherein the fixing clamps are C-shaped clamps with openings, and each of the openings being oriented outside or inside of an arcuate shape of the bent point of the resin tube.